Web analytics systems allow an operator of a web site to obtain statistics about requests for web pages made by visitors of the web site. The statistics may be generated from predetermined variables that are defined by the web analytics system or custom variables defined by authors (or content providers) of web pages for the web site. The operator of the web site typically purchases a specified number of custom variables and the authors define and assign specific attribute-value pairs to the custom variables. The authors are typically in the best position to define and assign custom variables to the content of a web page for the web site because the authors are most familiar with the contents of the web page. For example, the authors are typically in the best position to assign categories to a web page that the author has written. In many cases, the operator of a web site is a separate and distinct entity from an author (or content provider). Thus, the operator of the web site may not have knowledge of the attribute-value pairs assigned to a particular custom variable. In these cases, the operator of the web site is not able to generate reports based on specific attribute-value pairs of the custom variables because the attribute-value pairs are unknown to the operator of the web site.